The subject matter of the present disclosure broadly relates to the art of gas spring and damper devices and, more particularly, to performance-variable bushings that are dimensioned for securement between an end of a damper rod and an end member of a gas spring and damper assembly. Such performance-variable bushings can include an elastomeric connecting member that is at least partially formed from at least one of an electrorheological elastomeric material and a magnetorheological elastomeric material. In a preferred arrangement, such performance-variable bushings can be constructed for pre-loading associated with direct exposure to pressurized gas contained within a spring chamber of a gas spring and damper assembly. Gas spring and damper assemblies including such performance-variable bushings, and suspension systems can include one or more of such gas spring and damper assemblies are also included.
The subject matter of the present disclosure may find particular application and use in conjunction with components for suspension systems of wheeled vehicles, and will be shown and described herein with reference thereto. It is to be appreciated, however, that the subject matter of the present disclosure is also amenable to use in other applications and environments, and that the specific uses shown and described herein are merely exemplary. For example, the subject matter of the present disclosure could be used in connection with gas spring assemblies of non-wheeled vehicles, support structures, height adjusting systems and actuators associated with industrial machinery, components thereof and/or other such equipment. Accordingly, the subject matter of the present disclosure is not intended to be limited to use associated with gas spring suspension systems of wheeled vehicles.
Wheeled motor vehicles of most types and kinds include a sprung mass, such as a body or chassis, for example, and an unsprung mass, such as two or more axles or other wheel-engaging members, for example, with a suspension system disposed therebetween. Typically, a suspension system will include a plurality of spring devices as well as a plurality of damping devices that together permit the sprung and unsprung masses of the vehicle to move in a somewhat controlled manner relative to one another. Movement of the sprung and unsprung masses toward one another is normally referred to in the art as jounce motion while movement of the sprung and unsprung masses away from one another is commonly referred to in the art as rebound motion.
Gas spring and damper assemblies are well known and commonly used. Known gas spring and damper assemblies typically include a gas spring assembly and a damper (e.g., a hydraulic or fluid damper). The gas spring assembly can include opposing end members and a flexible bellows or sleeve secured therebetween to define a spring chamber suitable for containing a quantity of pressurized gas. The damper can include a damper housing and a damper piston located within the housing. A damper rod is connected to the damper piston and projects from the damper housing so that the damper piston and rod can undergo reciprocal motion relative to the damper housing.
In an assembled condition, the damper rod and damper housing extend into and through the gas spring assembly. Typically, the damper rod is connected to one of the end members of the gas spring assembly and the damper housing is connected to the other end member of the gas spring assembly. As such, forces and loads experienced during use of the gas spring and damper assembly can be transmitted between the end member and the damper rod by way of a damper rod bushing that is operatively disposed therebetween.
Conventional damper rod bushings of a wide variety of types, kinds and constructions have been developed to communicate forces and/or loads associated with the static and/or dynamic operation and use of a vehicle into, out of and/or otherwise between an end member of a gas spring assembly (or other vehicle component) and the damper rod. The static and dynamic inputs experienced by a vehicle suspension system can vary widely. For example, a vehicle suspension may experience relatively low frequency (e.g., 1-4 Hz) and higher amplitude inputs, medium frequency (8-12 Hz) and moderate amplitude inputs as well as higher frequency (e.g., 15-25 Hz) and comparatively lower amplitude inputs during use in operation. Conventional damper rod bushings are constructed to withstand forces and loads associated with all of such static and dynamic inputs. As such, some compromise with respect to the performance of conventional damper rod bushings typically results.
Notwithstanding the common usage and overall success of conventional designs, it is believed that a need exists to meet these competing and/or other goals while still retaining comparable or improved performance, ease of manufacture, ease of assembly, ease of installation, reduced cost of manufacture and/or otherwise advancing the art of gas spring and damper devices.